Control stick



1962 J. c. ZlEGLER ETAL 3,057,585

CONTROL STICK Filed May 29, 1959 5 Sheets-Sheet 1 AUTOMATIC PILOT l6 Z'7 AILERON ELEVATOR CONTROLLER CONTROLLER 10 & SERVO a.sERvo {I5 MOTORMOTOR E, A'LERON ELEVATOR ELEVATOR A'LERON 2 u .L 9.

INVENTORS' JOHN C. Z/EGL ER LUC/EN R. BEAUREGARD HARRY LAGER Oct. 9,1962 J. c. ZIEGLER ETAL 3,057,585

CONTROL STICK Filed May 29, 1959 5 Sheets-Sheet 3 FIG. 3

INVENTORS JOHN C. Z/EGLEP LUC/EN R. BEAU/PE 614/90 HARRY LANG/5R 0C1!-19623 J. c; ZIEGLER ETAL 3,957,585

CONTROL STICK 5 Sheets-Sheet 4 Filed May 29".) 1959' v QE D %m E 5 0"mzm 5 NR H M w L HARRY LAN ER Oct. 9, 1962 J. c. ZIEGLER ETAL 3,057,585

' CONTROL STICK Filed May 29, 1959 5Sheets-Sheet 5 FIG. 5

FIG. 6

INVENTORS 3 -JOHN CZ/EGLER LUC/EN RBE4U/QEGAPD HARRY LANGE/Q HTTUR/VEV II 3,857,585 Patented Oct. 9, 1962 3,057,585 CGNTRQL STICK John C.Ziegler, Maywood, and Lucien R. Beauregard, Rutherford, N .J., and HarryLanger, New York, N.Y., assignors to The Bendix Corporation, acorporation of Delaware Filed May 29, 1959, Ser. No. 816,785 2 Claims.(Cl. 244-83) The invention relates to improvements in an aircraftcontrol stick and more particularly to improvements in a control stickof a type such as disclosed and claimed in US. application Serial No.840,987 filed September 18, 1959 for reissue of U. S. Patent No.2,861,756 granted November 25, 1958 to Robert E. Feucht, John Jarvis andJohn -C. Ziegler and assigned to Bendix Aviation Corporation and to amanual control stick particularly adapted for use in a system formodifying or overcoming an aircraft automatic pilot control of a typedisclosed and claimed in the application for reissue of the aforesaidpatent.

In the control stick disclosed in the aforenoted patent, there areprovided deflection sensing synchros suspended exteriorly for thecontrol stick and through an interconnecting linkage arrangementeffective to sense a deflection of the control stick in a fore and aftor sideward direction so as to provide electrical signals for resettingthe auto matic pilot in a pitch or roll sense dependent upon thedirection and magnitude of the force applied to the control stick.

An object of the present invention is to provide a simplified andimproved control stick assembly in which the pitch and roll controlelements are mounted interiorly of a control stick column assembly insuch a manner as to avoid any external interconnecting linkage elementsand whereby no discernible cross coupling is effected between the pitchand roll channel control signals effected by fore and aft or sidewardmovement of the control stick.

Another object of the invention is to provide an improved control stickin which the force applied purely in a fore and aft direction or pitchsense results only in a signal in a pitch sense while a force applied toa sideward direction or roll sense causes a similar result by eifectingonly a signal in a roll sense; and the arrangement is such that forcesapplied to the control stick in both pitch and roll senses will producesignals that are proportional to the commands in the aforenoteddirections.

Another object of the invention is to provide an improved control stickin which a resilient column of the control stick is so designed andarranged that its deflection under load is known and maintainedaccurately and there is mounted interiorly of the column section highlysensitive, unidirectional, electrical pickup means. The electricalpickup means are carried by an inner member extending longitudinallywithin the resilient column. There are further provided armature meanscarried by the column and arranged in cooperative relation with thepickup means so that upon deflection of the resilient column rela tiveto the inner extending longitudinal member said armature meanscooperating with the electrical pickup means effects output signalsvarying in sense and magnitude with the direction and magnitude of thedeflective force applied to the control stick within the range ofdeflective movement of the resilient column relative to the innerextending longitudinal member.

Another object of the invention is to provide an improved control stickof the aforenoted type in which the resilient column is suitably slottedin a fore and aft plane and somewhat differently slotted in a sidewardplane so that a deflection of the control stick in a fore or aft direc-'tion by the pilot requires a distinctly different force than the forcerequired to effect a deflection of the control stick in a sidewarddirection and such that the control of the plane in a pitch or rollsense is accompanied by a control stick feel which approximates thatsensed by the pilot when flying under manual control. Moreover, in theaforenoted arrangement there is no discernible cross coupling betweenthe roll and pitch channels and a force applied purely in a pitch sensewill result only in a pitch signal and a force applied purely in a rollsense will result only in a roll signal while a force commanding bothpitch and roll will produce signals that are proportional to thecommands in each channel.

These and other objects and features of the invention are pointed out inthe following description in terms of the embodiment thereof which isshown in the accompanying drawings. It is to be understood, however,that the drawings are for the purpose of illustration only and are notintended as a definition of the limits of the invention, reference beinghad to the appended claims for this purpose. v

In the drawings wherein like parts are marked alike:

FIGURE 1 illustrates schematically a control stick embodying the presentinvention and shown in operative relation in a control system in whichthe invention is designed for use;

FIGURE 2 is a longitudinal view of the improved control stick with partsbroken away to illustrate operative mechanism therein;

FIGURE 3 is an enlarged longitudinal sectional view of the upper half ofthe control stick of FIGURE 2.

FIGURE 4 is an enlarged longitudinal view of the lower half of thecontrol stick of FIGURE 3.

FIGURE 5 is a sectional view of FIGURE 3 taken along the lines 55 andlooking in the direction of the arrows.

FIGURE 6 is a sectional view of FIGURE 3 taken along the lines 66 andlooking in the direction of the arrows.

Referring to FIGURE 1 there is shown schematically a control system suchas disclosed and claimed in the aforenoted US. Patent No. 2,861,756 inwhich the improved control stick of the present invention may be usedand in which the control surfaces of an aircraft may be operatedautomatically by an automatic pilot system denoted generally at 7 ormanually controlled by the improved control stick 8 forming the subjectmatter of the invention. The manual control stick 8 is mounteduniversally so that lateral or sideward displacements thereofeffectively control ailerons 9 through operation of a suitablecontroller and servomotor 10, as indicated diagram matically in thedrawing of FIGURE 1, while fore and aft displacements of the controlcolumn 8 in turn control elevators 11 through operation of a suitablecontroller and servomotor designated by the numeral 15.

Similarly as disclosed in the aforenoted US. Patent No. 2,861,756, pitchand roll sensing devices operating in the automatic pilot 7 applyelectrical signals through conduits 16 and 17 to motors 10 and 15 so asto effect operation of the elevators 11 and ailerons 9 to provide thedesired controlling action.

Upon an application to the manual control 8 of a force in excess of apredetermined value the defiective movement of a resilient columnthereof is effective to cooperate with a member extending longitudinallytherein, as explainedhereinafter, to impart a force to override theoperation of the controllers and servomotors 10 and 15 by the automaticpilot 7 and render the manual controlmotors 10 and 15 which made be ofthe type shown in FIG. 4 of the aforenoted patent and explained therein.

Improved Control Stick In accordance with the present invention,improved force translation means mounted interiorly of the controlcolumn 8 are electrically included in the signal chain so that byapplying to the manual control column 8 a force less than that requiredto overcome the operation by the automatic pilot 7 of the elevator oraileron servomotors 10 and 15, there is developed a signal proportionalto this force and in a sense or electrical phase depending upon thedirection of the application of force. The developed signal is appliedthrough a pitch setting channel conduit or a roll setting channelconduit 24 as the case may be and to either or both of the pair of lowpass filters 26 and 28 and through conduits 27 and 29 leading from thesefilters to the automatic pilot control system 7 to vary the setting ofthe automatic pilot system, as described in the aforenoted patent. Asexplained therein, the low pass filters 26 and 28 are provided so thatthe inertia of the pilots hand and the spring rate of the control columnwill not form an oscillating system in varying the setting of theautomatic pilot system 7.

The improved control column 8 forming the subject matter of the presentinvention is shown in detail in FIG- URES 2, 3 and 4 and includestherein a longitudinally extending member 30 rigidly secured at itslower end, as shown in FIGURE 4, by bolts 32 to a universally movableball-like joint member 34 mounted to a control pedestal 36, shown inFIGURE 1, by conventional means (not shown) so that upon appropriateforces being exerted on a collar 37 by a hand grip 38 at the upper endof the control column 8 and transmitted through improved means,hereinafter described, such forces are applied through the column 8 andthe ball-like joint member 34, including operating splines 39, so as toactuate mechanical linkages 40 and 4-2 to effectively operate, as shownschematically in the drawing of FIGURE 1, the con trollers 10 and 15 forthe ailerons and elevators 9 and 11.

As best shown in FIGURE 3, the collar 37 is secured by bolts 43 to theupper end of a resilient tubular column 45 which projects from the ballmounting 34 provided at the lower end thereof. As shown in FIGURE 4, thelower end of the column 45 is formed integral with the ball-like jointmember 34 so as to provide a one piece assembly which inherently lessensinternal hysteresis due to internal friction in the transference offorce applied at the hand grip 38 and through the column 45 and member30 to the universally movable ball-like joint member 34 and therebyprovide extreme accuracy in repeatable operation. The member 30 securedat its lower end to the ball-like joint member 34 further extendslongitudinally within the resilient tubular column 45 and in spacedrelation thereto. As shown in the drawing of FIGURES 2, 3, and 4, thereis provided a space 47 between the member 30 and the resilient tubularcolumn 45 and slots 49 in the column 45 in the fore and aft plane of theflexible tubular member 45 so as to permit the member 45 to flex in afore and aft direction relative to the member 30 upon an appropriateforce being applied at the hand grip 38 in a pitch controlling sense.Similarly, as shown in FIGURES 1 and 2, there are provided somewhatdifferent slots 51 in the column 45 located in opposite sides of theresilient tubular column 45 so as to permit the member 45 to flex in asideward direction relative to the member 30 upon a different forcebeing applied at the hand grip 38 in a roll controlling sense.

The slots 49 and 51 are so arranged in the resilient tubular column 45that control of the plane in a pitch or roll sense is accompanied by afeel of the control stick 8 which approximates that sensed by the pilotin operating the usual control stick when flying under manual control.

Limiting the tiexure of the resilient tubular column 45 relative to themember 30 in a fore and aft direction are adjustable stop bolts 53 screwthreadedly engaged in a 4 lower flange portion 55 of the collar 37 andextending radially into a space 57 within the collar 37.

The member 30 projects into the space 57 within the collar 37 and hasprovided at an upper end portion 59 thereof press fit inserts 60arranged to operatively contact the ends of one or the other of the stopbolts 53 so as to limit fiexure of the resilient tubular column 45relative to the member 30 in a fore or aft direction.

Further, as shown in FIGURE 5, similar stop bolts 63 in the collar 37cooperate with like press fit inserts 65 in the upper end portion 59 ofthe member 30 to operatively contact the ends of one or the other of thestop bolts 63 so as to limit flexure of the resilient tubular column 45relative to the member 30 in a sideward direction. The stop bolts 53 and63 thereby cooperate to prevent excessive relative movements of theseveral parts of the signal generators, hereinafter described, in foreand aft and sideward directions.

Further afiixed to the upper end portion 59 of the member 30 by a bolt67 is a spring element 71 fastened at an upper opposite end to a bracket73 pivotally mounted on a hollow pin 75 positioned in the collar 37 andarranged so as to tend to maintain the member 30 and resilient tubularcolumn 45 in a normal spaced relation one to the other under the tensionof the spring 71, as shown in the drawings of FIGURES 2, 3 and 4. Thehand grip 38 is attached to the collar 37 by a suitable bolt, not shown,which may pass through the hand grip 38 and hollow pin 75 so as tosecure the hand grip 38 to the collar 37.

In order to sense a deflection of the tubular column 45 relative to themember 30 in a fore or aft direction, there are provided variablereluctance pick up coils 75-76 and 77-7-3 fastened in the member 30 atopposite sides thereof by bolts 79 and 80 respectively.

The coils 75-76 are wound about electromagnetic core elements 81-82while the coils 77-78 are wound about electromagnetic core elements83-84. Fastened to the inner surface of the tubular column 45 by bolts86 and 88 are armatures 90 and 92 of a ferro magnetic material arrangedso as to cooperate with the electromagnetic core elements 81-82 and83-84 to vary the reluctance of the pickup coils 75-76 and 77-7-8 upon adeflection of the resilient tubular column 45 in a fore or aft directionrelative to the member 30.

The coils 75-76 and 77-78 form opposite arms of a normally balancedbridge circuit of a conventional type having suitable biasing resistorsand condensers as may be required mounted on a terminal board indicatedgenerally by the numeral 94 and positioned in the member 30, as shown inFIGURE 3.

The aforenoted bridge circuit has an input connected across a suitablesource of alternating current, not shown, and an output effective uponan unbalancing of the bridge circuit by the variance in the reluctanceof the pickup coils 75-76 and 77-78 to apply a signal of a controllingphase through the conduit 20 of the pitch setting channel of FIGURE 1.

The conduit 20 may be carried by a main conduit 95 leading from theterminal board 94 in the member 30, as shown in FIGURE 4, and may inturn lead to the low pass filter 26 and thereby to the automatic pilot 7for varying the pitch setting thereof to operate the elevator controller15, as described in the aforenoted Feucht et al. US Patent No.2,861,756.

Further in order to sense a deflection of the tubular column 45 relativeto the member 30 in a sideward direction, there are provided variablereluctance pickup magnetic material arranged so as to cooperate with theelectromagnetic core elements 106-108 and 110- 112 to vary thereluctance of the pickup coils 101-102 and 103-104 upon a deflection ofthe resilient tubular column 45 in a sideward direction relative to themember 30 to one side or the other thereof.

The coils 10110-2 and 103104 form opposite arms of a normally balancedbridge circuit of a conventional type having suitable biasing resistorsand condensers as may be required mounted on the terminal board 94 andpositioned in the member 30, as shown in FIGURE 4.

The last mentioned bridge circuit has an input conneeted across asuitable source of alternating current, not shown, and an outputefiective upon an unbalancing of the bridge circuit by the variance inthe reluctance of the pickup coils 110Z and 103104 to apply a signal ofa controlling phase through the conduit 24 of the roll setting channelof FIGURE 1.

The conduit 24 may be carried by the main conduit 95, as shown in FIGURE4, and in turn lead to the low pass filter 28 and thereby to theautomatic pilot 7 for varying the roll setting thereof to operate theaileron controller 10, as described in the aforenoted Feucht et al. US.Patent No. 2,861,756.

Upon one of the stop bolts 53 contacting an insert 60 or one of the stopbolts 63 cont-acting an insert 65 at the limit of permissible movementof the resilient column 45 relative to the member 30* in a fore or aftor sideward direction, as the case may be, a further force applied tothe hand grip 38 in the controlling direction will impart a directmovement to the member 30, ball mounting 34 and controlling pedestal 36,shown in FIGURE 1, so as to acutate the mechanical linkages 40 or 42 toeffectively control manually the operation of the controllers 10 and forthe ailerons 9 and elevators 10.

Thus there is provided an improved control stick of compact assemblageand accurate operation whereby during the operation of the automaticpilot system 7, the human pilot can by exertion of a force exceeding apredetermined amount set by the resilience of the resilient tubularcolumn 45 and the initial adjustment of the stop bolts '53 and 63,overpower the automatic pilot system and control the operation of theaileron and elevator surfaces 9 and 11 manually through the operation ofthe aileron and elevator controller mechanism 10 and 15, described inthe aforenoted Feucht et al. US. Patent No. 2,861,756.

Although but a single embodiment of the invention has been illustratedand described in detail, it is to be expressly understood that theinvention is not limited thereto. Various changes may also be made inthe design and arrangement of the parts without departing from thespirit and scope of the invention as the same will now be understood bythose skilled in the art.

What is claimed is:

1. A control stick comprising a resilient tubular column, a universallymovable ball-like member formed integral with a lower end of saidtubular column, a rod extending longitudinally within the tubular columnin spaced relation thereto, means afiixing a lower end of the rod to theball-like member at the lower end of the tubular column, said resilienttubular column having therein slot means in a first lateral plane andother slot means in a second plane perpendicular to the first lateralplane, said first and second mentioned slot means being arranged inspaced relation in said tubular column so that deflection of the tubularcolumn in said first plane may be effected by a different force thandeflection of the tubular column in said second plane, first stop meansfor limiting relative movement between the column and rod in said firstlateral plane, second stop means for limiting relative movement betweenthe column and rod in said second plane perpendicular to the firstlateral plane, said first and second stop means being mounted at anupper end of said column and in cooperative relation with an upper endof said rod, manually operable means mounted at the upper end of thetubular column for exerting a force on said column at said upper endthereof to deflect said column relative to said rod in said first andsecond planes, electrical signal developing means mounted within saidtubular column and between said rod and column to develop electricalsignals in response to deflection of said column relative to said rod insaid first and second planes, said signals varying in sense andmagnitude with said exerted force upon the force applied to saidmanually operable means being within a predetermined operating range,and said first and second stop means being effective to operativelyconnect said resilient tubular column to said rod upon the force appliedto said manually operable means exceeding said predetermined operatingrange, and control means operatively positioned by the ball-like memberat the lower ends of the tubular column and rod to efiect a controlfunction upon the column and rod being operatively connected asaforesaid.

2. A control stick comprising a resilient tubular column, a universallymovable ball-like member formed integral with a first end of saidtubular column, a rod extending longitudinally within the tubular columnin spaced rela tion thereto, means affixing a first end of the rod tothe balllike member at the first end of the tubular column, said tubularcolumn having slot means therein so arranged that a deflection of thetubular column in a first lateral plane may be effected by a differentforce than a deflection of the tubular column in a second planeperpendicular to the first lateral plane, manually operable meansmounted at a second end of the tubular column for exerting a force onsaid column at said second end thereof to deflect said column relativeto said rod in said first and second planes, electrical signaldeveloping means mounted within said tubular column and between said rodand column to develop electrical signals in response to deflection ofsaid column relative to said rod in said first and second planes, saidsignals varying in sense and magnitude with said exerted force upon theforce applied to said manually operable means being within apredetermined operating range, means to operatively connect saidresilient tubular column to said rod upon the force applied to saidmanually operable means exceeding said predetermined operating range,and control means operatively positioned by the ball-like member at thefirst ends of the tubular column and rod to effect a control functionupon the column and rod being operatively connected by said connectingmeans as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS2,393,892 De Ganahl Jan. 29, 1946 2,5 83,828 Gerstenberger Jan. 29, 19522,888,635 Volk May 26, 1959 2,895,086 Pettit July 14, 1959 2,934,292Visser Apr. 26, 1960

